Condenser



May 1928. LGGZ A. A. KENT CONDENSER Filed April 24. 1926 2 Sheets-Sheet l ATTORNEY.

May L 192s. 1,668,320

A. A. KENT CONDENSER Filed April 24, 1926 2 Sheets-Sheet 2 Panarea May i, leas.

UNITED CONDENSEEP.

'Application tiled April 24, 1926i. Serial llo. Mlll.

My invention relatesto variable electrical condensers of the plate type for variation ot capacity, as in tuning ot circuits, particularly circuits traversed by high frequency current or oscillations, as in radio systems.

ln accordance with my invention, there is provided a condenserI unit comprising a member, yoke or bracket supporting the rotor element to which, independently of the rotor and its support, is secured the stator element, and more particularly, the structure for securing the stator element to the aforesaid bracket comprises a second yoke or bracket comprising inwardlyextending arms or ledges to each ot' which is secured a platelike member ot' relatively rigid insulating material.

More particularly in accordance with my invention, the condenser unit aforesaid comprises a yoke or bracket having rearwardly extending arms or ledges disposed, respectively, preferably' at angles of exactly ninety degrees with respect to the main yoke or bracket section and to each arm or ledge there is secured a plate-like member of insulating material for supporting the stator assembly which comprises members lwhose outer surfaces lie, respectively, in the same planesras-the outer surfaces of the aforesaid arms or ledges, the aforesaid plate-like members of insulating material having one or more sllots elongated along'a lineextending at right angles with respect to the mam yoke or bracket section and through which pass screws or the like tor adjustably securing the stator assembly in 4vany desired position axially of the rotor assembly.

Further in accordance with my inventionI the stator structure is supported upon a yoke or bracket having arms extendin vinwardly at true right-angles to the main liar of the bracket, said arms being adjustably supported, respectively, upon rearwardly eX- tending insulation arms of the rotor supporting yoke or bracket.

vFurther in accordance with my invention the bracket or yoke supporting the rotor bearing sleeve is provided on its side 0pposite the rotor assembly with a spring exerting thrust upon the rotor shaft longitudinally or the axis of rotation oit the rotor for maintaining pre-determined bearing pressurey between the conical bearing surfaces ot the bearing sleeve and rotor shaft;

more particularly, this spring is locked into 'a circumferential slot on the rotor shaft and further retained against movement about the rotor shaft by one or more pins in the supporting vyoke received by an aperture or apertures `in the spring.

Further inaccordance with my invention, there-is provided a novel torna of stopstructure, preferably ot a yielding character for preventing rotation ot the condenser rotor element beyond a pre-determined point in its cycle of'rotation.

My invention resides in condenser structure of the character hereinafter described and claimed.

For an illustration ot'some of the various forms my invention may take, reterence is to be had to the accompanying drawing in which:

Fig. 1 is a vertical sectional view of apparatus constructed in accordance with my invention. y

Figs. 2 and 3 are, respectively, rear and top views of the `apparatus shown in Fi 1. Figs. 4 and 5 are sectional views taken respectively, on the lines 4 4 and 5 5 of Fig. 1.

Fig. 6 is a ,sectional view taken on the line 6 6 of Fig. 4.

. Fig. 7 is an elevational view of one form of bowed spring.

Fig.- 8 is a vertical section of apparatus of a slightly modified form.

Fig.y 9 is a rear view of a condenser showing *the rotor plates entirely without the stator' plates.

Fig. 10 is a front elevational view of the structure shown in Fig. 8.

Fig. 11 is a sectional view taken on the line 1]. 11 of Fig. 10.

Fig. l2 is an elevational view of a rotor shaft.

Fig. 13 is an elevational view of a modified form of bowed spring.

ln my co-pending application Serial No. 99,696, liled April 5, 1926, upon which issued Letters Patent No. 1,658,562,'February V7, 1928, there is illustrated a radio receiving yset comprising a plurality of tuning devices, as variablecondensers, all mounted in spaced relation on a panel with their axes normally occupying a horizontal position. ln that application, there are illustrated three condensers all actuated by a single knob or handle mounted exteriorly of the front cabinet wall on the rotor shaft of the middle condenser extending therethrough, the two condenser rotors on either side being controlledby belts or bands actuated by a pulley on the, shaft of the middle ,condenser and which pass, respectively, over pulleys secured to the rotor shafts of the adjacent condensers.

In single control apparatus of that character, it is lessential that all condensers utilized for tuning the various circuits be duplicates of each other, at least in so far as concerns their electrical or capacity characteristics.

ln this application, there are illustrated and described condenser structures of the character above set forth, utilizable as a part of the apparatus disclosed in my aforesaid lietters Patent. However, it shall be understood that such condensers may be utilized in any other desired manner, for example, individually in conjunction with the customary dial for manual operation.

Referring to Fig. 1 of the drawing, 1 is a member, as a panel or wall, serving as the support for elements of a radio receiving set. Panel 1 may be secured interiorly of a cabii net to a wall thereoL-as disclosed in my las aforesaid application.

Suitably secured to the panel 1, as by screws 2, is the bracket, frame or yoke 3 terminatin in the upper and lower horizontal arms, shelves or ledges 3 and 31?, which should extend, respectively, fromthe yoke or frame 3 at'angles of 90 degrees. 'lo they upper and lower horizontal ledges 3a and 3b are secured, respectively, in s any suitable manner, as by one or more rivets 4, the members or plates 5 of insulating material, as av phenol condensation product, hard rubber, or a fabric, as linen or canvas, impregnated with a phenol condensation product or the like. As herein shown, plates 5 are formed of impregnated canvas, as described above, and are secured, respectively, to the upper and lower angular portions or arms tfa and 6lb of la second oke or bracket 6 in any suitable manner, as y the screws 7 or the like passing through the slots 5 of plates 5, Figs. 3 and 11, elongated in a direction extendin at right angles from the vertical portion o `frame 3 as viewed in Figsf land 8. Alinac- 'cordance with my invention, the arms 6a and 6b should extend from the vertical portion of bracket 6 at angles of 90 degrees, and the outer surfaces of said angular portions should preferably lie, respective-ly, in the same planes in which lie the outer surfaces of the arms or ledges 3a and 3b of frame 3. Preferably, awasher plate 8 or. the like is disposedon each plate 5 between the-heads of screws 7 and the'outer plate surface.

'ljo the end that frame 3 may be secured in predetermined position on panel 1, two or more inwardly extending prongs or lugs neeaeao 2a, preferably formed integrally with said" frame,are received by correspondingly positioned openings in panel 1.

Supporting members 9, as bolts, screws or the like, pass, respectively, through bracket 6 adjacent its arms 6a and 6b, and supported by said vmembers 9 are the stator plates 10 held in spaced relation thereon by washers 11 or the like. ln the example shown, members `9 0r, and as illustrated, the

thereof, as viewed in Figs. 1 and 8, is

mounted in an opening or perforation therein, and maintained in predetermined rightangular relation'withrespect thereto in any suitablemanner as by pressing or pee'ning the end 15a of said member on tothe adjacent portion of said frame. Mounted in bearing member 15 is `a shaft 16 carryin the rotor plates 17 held in spaced relation thereon by washers 18, said rotor plates interleaving with the stator plates '10. Rotor shaft 16 comprises a conical bearing 16a and a reduced portion 16. As clearly indicated in Fig. 1, shaft 16 has two bearing surfaces on member 15, namely, in the region where conical bearing 16 engages the tapered end of member 15 and'where the cylindrical por- 'i tion of shaft 16 enga-ges the portion 15b of reduced diameter of member 15. Between these two bearing surfaces, shaft 16 and bearing member 15 are in non-contacting relation, whereby the friction between the parts is reduced and shaft 16 is more readily maintained in proper aligned position. 'llt lll@ desired, rotor shaft 16 may be provided with ed, spring 21 engages a washer 22 in turn engaging a ptulley, dial or the like 23 secured to said sha for exerting thereon a longitudinal thrust toward the left, Fig. 1, to bias conical bearing 16a int-o engagement with its seat onthe endo'f member 15, wherei by the rotor plates 17 are properly positioned within the stator plates 10.

lf desired, rotation ot' spring 21 with respect to its shaft 16 may be prevented by `passing a lug 23 on condenser frame 3 into may . at the end of bracket 26.

an opening or. aperture 25 at or adjacent the springen Suitable stop structure may be provided for limiting the extent of rotation of the condenser rotor. For example, it is desirable to thusrestrict such rotation when the rotor plates have beenmoved to positions either wholly within or wholly without the stator plates. To this end,.there -may be utilized counter-balance weight 19 on shaft 16' in' conjunctionwith suitable stop struc# ture herein disclosed-as comprising a bracket 26 or the like, suitabl secured, as by a spot welding operation, to the interior surface of the plate or bracket 3 below rotor shaft 16. By providingtwo or more inwardly extend,- ing prongs or lugs 27 on plate3, bracket 26 secured in predetermined position t-hereon when correspondingly positioned openings on said bracket receive the lugs 27 aforesaid, Figs. 2 and 4. Bracket 26, in the example shown, comprises three angularly extending armsI or flanges 26a. Rising from the centrally disposed flange 26* is a lug or projection, 26b entering an aperture in a member 28, preferably of resilient material, rest-ing upon the centrally disposed flange 26'* and passing beneath the similar flanges The ends of member 28 are positioned in the path of counterbalance weight 19 and, preferably, such ends are upturned, as indicated at 28, Figs. 2 and 4, to constitute the stops.

Referring to Fig. 9 which is a rear View of the rotor and stator structures of either Figs. 1 or 8, and assuming that the stator plate structure is positioned vertically as shown,y it is necessary, when the rotor plate structure is entirely without the stator plate st-ructure, for counterbalance 19 to be tilted as shown, to effect proper counterbalancing action on said rotor plate structure. `.Accordinglv, when so arranged, to restrict rotationv of the rotor plates, either when wholly within or wholly withoutthe stator plates, bracket 26 and resilient member 28 should be tilted or inclined at an angle from the true horizontal plane, as indicated in Fig. 10.

In Fig. 8, I have illustrated a form of condenser whose rotor shaft may be mechanically coupled or connected to a manuallyoperated rotor shaft/of another condenser: or utilized las a single condenser with a dial manually operated. The'tuning structure, namely rotor and stator, or that lying to the right of and including the condenser frame or bracket 3, should be and preferably is a duplicate of the corresponding structure illustrated in Fig. 1. Moreover, stop-structure for preventing over-traveling of the rotor shaft is ordinarily not required on a condenser which is coupled or lconnected to a condenser like that shown in Fig. 1, which .already includesstop-strueture for preventingover-traveling of its rotor shaft. 'Accordingly, the condenser of Fig. 8 is shown,

without rotor shaft' stop-structure of any kind.

When the condensers of Figs. 1 and 8 are mounted side by side on the same panel, it is desirable that the condenser frame 3 of the condenser of Fig. \1 be non-adjustably mountedon said panel, whereas the similar frame 3 of the condenser of Fig. 8 is preferably mounted for adjustment in a horizontal direct-ion on said panel. To this end, panel 1 `may be provided with the slots 30 elongated in a horizontal direction, as viewed in ig. 10, through which pass the lugs 2 projecting transversely of frame 3. Panel 1 should also be provided with the similarly elongated slots 31 through which Kpass the screws 2 or the'like for securing frame 3 t0 said panel. In aconstruction of this character it is desirable that there be utilized 'a washer plate 32 extending between the two horizontally aligned screws 2 and located between the said screws 2 and plate or member 1 shown near the top of Fig.,10.

The rotor shaft 16 of the condenser of Fig. 8. in the example shown carries a pulley 33 of a width slightly greater than the width of the belt, band or the like 34 driving the same from the manually operated rotor shaft of the adjacent condenser, which may be the condenser shown in Fig. 1 carrying a pulley 23 mounted on its rotor shaft 16. Mechanical coupling ofl rotor shafts with associated features is claimed in my applica` tion Serial No. 79,100, filed January 4, 1926. Due to the construction described above for adjusting the condenser of Fig. 8 horizontally on its supporting panel and, as described 1n my application, Serial No. 244,605, filed January 5, 1928, the proper degree of tension may be imparted to the belt or band 34 extending between the two condensers.

In the example-illustrated. the rotor shaft 16 ofthe condenser of Fig. 8 is a duplicate of the rotor shaft illustrated in Fig. 1, with the exception that in Fig. 8 shaft 16 is somewhat shorter and, moreover, is provided with a circun'iferential groove 35, Figs. 8 and 12. The larger diametrical portion of aliey- .shaped slot disposed centrally of a bowed spring 36, Fig. 13, may be passed along the rotor shaft 16 illustrated in Fig. 8 when the pulley 33 is removed therefrom. lVhen spring 36 is in substantially the position indicated in Fig. 8. it may be moved transversely of said shaft to position the periphery of the small diametrical portion of the aforesaid key-shaped slot. in the circun'iferential groove 35. lVhen thus positioned, spring 36 exertsl an axial thrust on shaft 16 to maintain conical bearing 16a in engage ment with its seat on bearing member 15.

lf desired, rotation of spring 36 with respect to its shaft 16 may be prevented by alii passing a lug 2a on condenser frame 3 into an opening or aperture 37 at or adjacent the spring end. c

In a structure of the character illustrated by Fig. 1 the tension of the spring 21 is determined by the position upon the shaft 16 at whichfis secured the operating knob or dial or the pulley Q3. In Fig. 8 the tension of the spring 36 is independent of the position of the operating knob or dial, or pulley 36, upon the shaft 16 and is dependent upon the position of the left shoulder of the shaft groove 35 with respect to the front face of the bracket or yoke member 3 upon which the spring bears.

In the arrangement of Fig. 8, wherein the spring 36 engages at its aperture against a shoulder of the groove 35 of the rotor shaft 16, the lug 2 engaging in the notch 37 at the edge of the spring holds the spring not only against rotation, but also locks it in operative position as regards its thrust upon the shaft 16. To remove the spring its notched end 37 is lifted to clear the lug 2a, whereupon the spring may be moved to position where the larger portion of its aperture registers with the shaft 16, whereupon the sprmg may bc withdrawn over it.

The rotor plates 17 may be moved, particularly as indicated in Fig. 9, for example to position in which there is no interleaving` with or overlap of the stator plates 10. It may then obviously be withdrawn from the condenser structure orjunit if the structure otherwise permits, and thisis thc fact', for

simply by moving the spring 36 transversely of the shaft 16 from its thrust exerting-position, assuming the pulley 33 removed, the rotor element or unit as a Whole is Withdrawable toward the right, Fig. 8. rli`his is possible further because the spring operates upon a shaft in a singlebearing system and where the thrust of the spring holds the shaft in its normal bearing position.

Condenser structures in large quantitiesof the types above described may be readily assembled with the assurance that there Will be little or no variation between individual condensers without the aid of any substantial amount of skilled labor. To this end, it is important that close attention be paid to the formation of the individual condenser parts and to the correct assembly thereof.

For example, the condenser frames 3 should always be duplicates, and the portions or ledges 3a and 3* thereof should extend fromthe vertical portions of frames 3, Figs. 1 and 8, at angles of 90 degrees. The

somewhat similar bracket 6 should likewise be so formed thatits ledges or flanged portions 6a and 6b extend from the vertical portion of said bracket 6, Figs. 1 and 8, at anv gles of90 degrees. Moreover, the outer surfaces of the pairs of ledges 3, 6 and 3", 6b should preferably lie .in the same planes,

meegaan thereby presenting an even surface for the plates 5.

Obviously, the various plates entering into the stator. assembly should be duplicates both as regards configuration and thickness, as should the plates` for the rotor assembly. rlhe. spacing washers for the stator plates should invariably have the same thickness. The washers forthe rotor platesshould likewise'be carefully graded.

' The bearing member 15 for the rotor shaft when secured to frame 3 should extend at an angle of 9G degrees with vrespect thereto so as to be in parallel relation with the pairs of ledges 3a, 6n and 3b, 6".

All of the rotor shafts, no matter for which type of condenser, should be of the same length, except that the shaft of one condenser should be longer to extend to the exterior of the cabinet where there isv attached a knob or dial for unior single dial co'ntrol.

After the various parts have. been assembled in the proper manner. but before screws 7 have been tightened, and while the' bowed spring is exerting a thrust on the rotor shaft to maintain its conical bearing in engagement with its seat, a suitable gauge or the like should be passed between adjacent rotor and stator plates to ensure proper spacing thereof, whereupon screws 7 may be tightened, .to clamp plates 5 to the respective ledges 6 and 6b for properly positioning the stator assembly with respect to the rotor assembly. l

A careful observance of the various manufacturing operations of the various parts, together with the proper assembly thereof, of which the foregoing are the most important, will ensure large scale production and at' the same time eliminate the heretofore necessary time-consuming tests of the electrical characteristics of each individual condenser.

Mechanical coupling of rotors of condensers and their mountings and associated features of the character herein disclosed are claimed in my aforesaid application Serial No. 244,605, filed January 5, 1928.

What l claim is:

l. In a condenser unit, a frame compris,- ing a. mainfsection and a ledge meeting at right angles, a rotor element supported by said frame, a stator element, a second frame directly connected to said stator element comprising a ledge lying in the plane of said mst-mentioned ledge, and means for connecting said ledges to secure said stator element in position.

2. The combination with a frame, of a stator element secured in fixed position with respect thereto, a rotor element whose shaft extends through said frame, and a bowed spring having a key-shaped slot, the slot at its smaller diameter lying within a circumferential groove of the shaft.

so 'y lill :tessere movement oi said rotor element and shalt.

Condenser structure comprising a frame, a stator element secured in dried positionsvith respect thereto, a rotor element having a shalt vextending through said trame, a countervveiglit element on said shalt, a loracltet carried loy said trame, and member detachably carried by said loraclret for engaging said counteriveight element to limit rotative movement et said rotor element and shaft. i

5. An condensercomprising a trame, a rotor element supported hy said traine, a stator element, thin plates et insulating material secured to said trame and of sulostan tial Width in a plane normal to the face et said trame, and means including said plates for adjustably supporting said stator element upon said trame in operative position with respect to said rotor element.

6. A condenser comprising a :ti-ame, a rotor element supported ley said trame, a stator element, and thin plates ot insulating material secured to said trame and ot substantial width in a plane normal to the tace of said trame, tor supporting said stator element upon said frame, said plates being provided with slots to permit adjust-ment ot' said stator element with respect to said rotor element.

7. 'lhe combination with a trame, ot a rotor element having a shaft extending through said trame, a stator element held in operative relation with respect thereto, and a spring having a slot of dierent Widths,l the slot at its greater Width permitting movement or the spring axially of said shaft and at a lesser Width lying Within e circumferential groove of the shaft to exert a thrust thereon.

8. Condenser structure comprising in comhination a metal frame having an' integral arm having a flat tace extending at right angles, thereto, a rotor element Whose axis is parallel to said arm, a stator element having a tlat tace Whose plane is parallel to the anis or said rotor element, a plate ot insulating material having a large area parallel to the dat faces ot said stator element and arm, respectively, and secured tlatwise to said laces of said stator element tor securing said stator element to said trame, and means including saidplate ot insulating material for edecting relative adjustment between said stator and rotor elements.

9. Condenser structure comprising in comleinen-,ion a metal trame having integral having dat laces extending at right angles thereto, a rotor element, a stator element, second metal trame comprised in said stator clement, integral arms on said second fr having ilat t'aces extending at right thereto toward said iirst named arms, ot' insulating material having large paralleijto the faces oit the arms o trames and secured tiatvvise thereto, means tor adjusting each ot said plates respect to one et said trames to eileet tive adjustment iietveen said rotor stator elements..A

l0, Condenser structure comprising combination a metal trame having integral arms extending at rioht angles thereto, a rotor element, a stator element, a metal trame having integral arms extending at right angles thereto, said stator ele comprising u plate assembly secured to said second trame between its arms, and plates ot insulating material each having alarga area parallel to the arms oi" Said trames, and means for securing each et said plates to arms ot' said trames and adjustably with respect to an arm ot one oit said Jtrames Jfor supporting said stator element in operative relation to said rotor element.

l1. Condenser structure comprising in combiimtion a pairot metal trames each having integral arms extending right angles thereto, a rotor element, a stator element, the arms et diderent trames spaced from each other longitudinally ot the anis ot'lthe rotor element, and plates oi insulating material having large areas parallel to the faces ot' said arms and overlapping the arms ot the diierent trames and adiustaiily securing them to each other, said stator ele-- ment carried hy one oi said trames, and said rotor element carried solely by the other said trames.

i2. Condenser structure comprising the combination with a support, or' rotor and stator elements, said rotor element having a shaft with portions of different diameters to torna a shoulder, a plate spring engaging said support and` having, an aperture embracing said shaft and thrusting against said shoulder, and a member carried by said supv port holding said spring it is shoulder-engaging position.

13. Condenser structure comprising the combination with a support, of rotor and stator elements, said rotor element having a shaiit with portions ot' diderent diameters to t'orm a shoulder, a plate spring engaging saidsupport and having a slot of diiierent Widths, the slot at its greater width permitting movement ot the spring axially oi said shat't and at a lesser Width engaging said shoulder to exert an axial thrust on said shaft, and means carried ley said support and engaging said spring at an edge thereof for .holding it in its thrust-exerting position.'

la. Condenser structure comprising the combination with a support, of rotor .and stator elements, said rotor element having a shaft with portions of different diameters to form a shoulder, la plate spring engaging said support andhaving a slot of different Widths, the slot at its greater Width permitting movement of the spring axially of said shaft and at a lesser width engaging said shoulder to exert an axial thrust on said shaft, and a stud carried by said support, said spring having at its edge a notch engaging saidstud to hold said spring in its thrustexertin position.

' 15. ondenser structure comprising the combination with a support, of'a stator element, a rotor element having a shaft having a circumferential roove to form a shoulder, said rotor element eing rotatable to position in which itis free of interleaving relation with said stator element, a single bearing for said rotor element carried by said support, and a plate spring engaging said support and movable transversely of said shaft and having an aperture at which itengages said shoulder to exert on said shaft an axial thrust to hold said shaft inoperative relation with respect to said bearing,'said rotor element being removable in an axial direction upon removal ofsaid spring from said groove. y A

` 16. The combination with a rotor element of a condenser, of yielding stop structure comprising a member included 1n said element and a leaf spring engaged thereby, and a fixed abutment towards which said spring is biased and serving to dene the rotor stopping position of said spring.

17. The combination with a rotor element of a condenser, of yielding stop structure therefor comprlsing a pair of abutments, a third abutment between them, a leaf spring extending over said third abutment biased against the under sides of said pair of abutments, and means movable with said rotor element 'adapted to engage said sprin at points on opposite sides of said third .a utment and in directions opposite to the direction of bias of said spring.

18. Condenser structure `comprising in combination a metal frame having an integral arm having a flat face extending at right angles thereto, a rotor 'element mounted solely on said frame and Whose axis is parallel to said arm, a second metal frame having an integral arm having a fiat face extending toward said first named arm and spaced therefrom longitudinally of the axis of said rotor element, a stator element secured directly to said second frame independently of its arm, and a thin plate of in' sulating material secured to said arms flatwise against their said flat faces for securing'said stator element to said rst named frame.

ARTHUR ATWATER KENT. 

